There has been a need for a method for the removal of cured thermoset polyurethane foamed potting material from multitiered electronics packages in ammunition (EP package). The objective is to perform a technical analysis of the electronic guidance and fuse systems used for the ammunition. This is done in order to determine the electronic components, the engineering, functional circuitry and overall performance of the ammunition.
Before the electronics analysis can be performed, a method is needed to remove the solid thermoset foamed polyurethane polymer (potting material) in which the individual electronic systems were encased. Being thermoset, the cured polymer was very hard and unaffected by most common polar and nonpolar organic solvents.
Concentrated and fuming sulfuric acid materials did readily attack and dissolve the polymer but left an acid residue which was both dangerous and corrosive to many of the electronic components. In addition, the printed identification on the individual components was often removed or rendered illegible.